<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

<div id="app">
<button v-on:click="sayHi">click Me</button>
</div>

<!--导入Vue.js-->
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>

<script>

    var app = new Vue({
        el: '#app',
        data: {
            message: "gao"
        },
        methods: {
               sayHi: function (){
                   alert(this.message)
               }
        }
    })
</script>

</body>
</html>